Safety trip means for sheet feeding mechanism



Nov. 27, 1962 H. E. CAMPBELL ET AL 3,065,961

SAFETY TETE MEANS FOR SHEET EEEDING MECHANISM Filed Aug. 17, 1960 4 Sheets-Sheet 1 will um Nov. 2 7, 1962 H. E. CAMPBELL ErAL 3,065,961

4 SAFETY TRIP MEANS FOR SHEET FEEDING MECHANISM Filed Aug. '17, 1960 4 Sheets-Sheet 2 Arrx Nov. 27, 1962 H, E, CAMPBELL ETAL 3,065,961

SAFETY TRIP MEANS FOR SHEET FEEDING MECHANISM Filed Aug. 17, 1960 4 Sheets-Sheet 3 Arr-x SAFETY TRIP MEANS FOR SHEET FEEDING MECHANISM Filed Aug. 1'7, 1960 Nov. 27, 1962 H. E. CAMPBELL ETAL 4 Sheets-Sheet 4 /////////r//r v/ daf/xv 415650 caw/vou y United States 3,065,961 SAFETY TRIP MEANS Eon SHEET FEEDING MECHANISM This invention relates to mechanism for feeding paper or other sheets one at a time from a stack thereof, and refers particularly to stream feeders of the kind commonly used in high speed printing machines for supplying paper sheets in overlapped relationship.

It is known in such printing machines to provide trip mechanism which operates automatically to stop the operation of the feeder if the leading sheet of the stream thereof is disposed rearwardly of its correct position so that it fails to reach the gripper lays.

It sometimes happens however that the leading sheet of the stream is disposed so far forwardly of its correct position that it passes below the lays while the latter are raised, in which case it may pass in a folded or crumpled condition into the nip of the impression cylinder or two or more sheets may pass thereinto, and in either case, the machine may be seriously damaged as the aforesaid known trip mechanism serves only to stop the feeder in the case of an under-run of the sheets and not in the case of an overrun thereof.

More particularly the said known under-run trip device comprises a transversely extending trip spindle arranged somewhat above and rearwardly of the lay bar so that the stream of sheets pass below 4the said spindle before reaching the gripper lays. This trip spindle is provided with two or more depending arms, each having a finger pivotally connected to its free lower end. These fingers extend forwardly, that is, towards the lays, and the free ends thereof are bent downwardly so as to rest on and slide over the surface of a sheet of paper when the latter is in contact with the gripper lays, at which time the forward portion of the sheet rests on and is suported by a transversely extending bar in the usual way.

The trip spindle is oscillated in timed relation with the feeder in such a manner that the free ends of the fingers slide over the sheet at the leading end of the stream and towards the lay edge of the said sheet immediately after the latter has compelted its forward movement, at which time it should be in contact with the griper lays. If however the said leading sheet is underfed so that it does not reach the lays, the said fingers in moving forwardly, pass over the lay edge of the sheet onto the said supporting bar and drop into corresponding slots formed therein. The trip spindle is thus prevented from completing its full movement so that associated mechanism operates to stop the feeder until an appropriate adjustment is made.

If however the sheet is in contact with the lays, it covers the said slots so that the trip mechanism does not operate. The same is also true if the sheet should over-run the lays so that it does not protect the machine against the risk of damage from this cause.

It is an object of this invention to provide means which operate to prevent damage to the machine if a sheet should over-run the lays.

AccordinglyV the invention includes safety means for association with sheet feeding mechanism, comprising at least one over-run detecting finger, means operable for moving the said fingerin timed relationship with the sheet feeding mechanism is a path intersecting the path of edarent vancement of sheets by said sheet feeding mechanism and directly forward of the position of a correctly advanced sheet, and control means operable in response to obstruction of the movement of said finger.

The control means may be utilised to stop the machine being fed by the sheet feeding mechanism, and/ or to release pressure on the printing machine roller, and/or it may be utilised to stop the operation of the feeding mechanism.

In its application to a printing machine, the invention may comprise one or more over-run detecting fingers and means operable in timed relation with the feeder to raise and lower the said fingers immediately in front of the lays, and means operable if the downward movement of the fingers is obstructed to stop the operation of the feeder, and preferably of the machine as well.

Thus if the leading edge of a sheet is in contact with the lays, the said fingers are free to descend, whereas, if the sheet has over-run the lays, it is disposed in the path of downward movement of the fingers so as to arrest the latter. For this purpose the said fingers are preferably pivotally mounted and are actuated in such a manner that they are positively moved in the upward direction only.

More particularly, each of the said over-run fingers is preferably pivotally connected to the oscillatable lay bar and are arranged to be raised and lowered thereby, and to close corresponding switches in a control circuit if they fail to complete their downward movements, the said switches when operated, serving to stop the machine.

Alternatively or in addition, provision may be made whereby the aforesaid existing trip spindle is prevented from completing its forward movement if an over-run finger is arrested before completing its downward movement whereby the eXisting trip mechanism operates to stop the operation of the feeder.

It sometimes happens that the following edge portion of a correctly fed sheet is curled upwards to such an extent that it engages and lifts the over-run fingers as it passes the latter, and in order to prevent the tripping of the safety mechanism in such circumstances the aforesaid control switches are preferably connected in circuit with a further switch which is closed only when the lays are down.

The foregoing and other features of the invention will be explained in the following description of a preferred form thereof. In this description reference is made to the accompanying drawings wherein:

FIGURE 1 is a plan view of part of a sheet feeding mechanism embodying the safety trip means according to this invention,

FIGURE 2 is a perspective view of part of the trip means,

FIGURE 3 is a view in sectional side elevation illustrating the operation of the trip means when sheets of paper are feeding correctly,

FIGURE 4 is a view in section on line 4--4 of FIG- URE l, showing a switch in closed position,

FIGURE 5 is a view similar to FIGURE 4 showing the switch in open position,

FIGURE 6 is a view corresponding to FIGURE 3 showing the position of an over-run finger and associated parts in disengaged position,

FIGURE 7 is a view similar to FIGURE 3 showing the operation of the safety trip means when a sheet of paper has been advanced beyond the correct position, and

FIGURE 8 is a diagram of he circuit means for interrupting the sheet feeding.

The drawings illustrate part of a sheet feeding mechanism comprising two side plates 11 which support in bearings a lay bar 1 2 and a trip spindle 13 The trip spindle and lay bar extend horizontally and parallel to each other, the trip spindle being raised above the lay bar and being disposed rearwardly thereofie. towards the direction from which sheets of paper are advanced by the feeding mechanism. The feeding mechanism forms n part of this invention, and for simplicity it will not be described. l

The trip spindle 13 carries two depending arms 14 each of which has a boss 15 through which the trip spindle is inserted. The bosses 15 are secured to the trip spindle 13 by set screws 16 so that the arms 14 are spaced laterally from each other by a suitable distance. Each depending arm 14 is provided at its lower end with a laterally extending pivot pin 17 on which is mounted a block 18. The blocks 18 each carry a finger 19 fixed to the block and extending forwardly i.e. towards the lays of the machine. The free ends 20 of the fingers 19 are bent downwardly so that they may rest on and slide over the surface of a sheet of paper 21 supported on a transversely extending bar 22. Each of the depending arms 14 carries a leaf spring 23 fixed to a lug 24 on the arm and engaging a projection 25 on the block 18. This spring serves to urge the finger 19 downwardly.

The mechanism so far described is already known and serves `to stop the feeder in the event of failure of the feeder to feed sheets forwardly to the required extent. Thus the trip spindle 13 is oscillated in timed relation with the feeder so that the free ends 20 of the fingers 19 slide over the sheet 21 at the leading end of the stream, immediately after the sheet 21 has completed its forward movement. At this stage the sheet 21 should be in contact with the gripper lays (not shown), and if it is correctly positioned it covers a slot 26 which extends transversely in the upper surface of the bar 22. The ends 20 of the fingers 19 then pass over the slots 26 and are prevented by the sheet 21 from engaging in the slot 26. However if the sheet is under-fed and does not reach the lays, the slot 26 is not covered and the free ends 20 of the fingers engage in the slot and are thereby arrested. This prevents the trip spindle 13 from completing its full movement, and associated mechanism (not shown) operates to stop the feeder until an appropriate adjustment is made.

As previously indicated, the mechanism thus far described will not function to protect the machinery if a sheet should over-run the lays. The additional mechanism which is -provided by this invention to achieve this purpose comprises two blocks 27 attached to the lay bar 12. Each block 27 is bored to receive the lay bar 12 and is split diametrically, the two halvesof the block being secured together by screws 28 whereby the blocks can be clamped on the lay bar at suitable positions. Each block 27 is clamped approximately in alignment with one of the under-run detecting fingers 19.

Each block 27 carries a smaller block 30 (hereinafter termed a rocker) which is pivotally supported on the block by means of an integral spigot extending into a bearing hole in the block 27 para'lel to the axis of the lay bar 12. Each rocker 30 has an integral rearwardly projecting tail 31 and each rocker also carries an over-run finger 32 comprising a length of rod inserted through a hole in the rocker and fixed to the rocker by a grub screw 29. Each finger 32 is bent so that it extends upwardly over the lay bar, and has a straight intermediate portion which can rest on the lay bar and extend downwardly and forwardly as illustrated in FIGURE 3, when the lay bar is in the angular position shown in FIGURE 3. The forward end 33 of each over-run finger 32 is inclined downwardly, so that it will rest on a sheet of paper if a sheet is disposed below it. In FIGURE 3 the lay bar is shown in its extreme forward angular position. During the operation of the mechanism the lay bar is oscillated rearwardly from this position to that shown in FIG- URE 6, and it will be evident from this figure that in moving the -partial rotationA of the blocks 27 causes' thev fingers 32 to be raised well clear of the advancing sheets of paper. The fingers 33 are provided with tension springs 34 connected between them and pins 35 on the blocks 27. The springs 34 thus urge the fingers 32 to remain in contact with the lay bar 12, but permit them to be lifted from it if they strike an obstruction. As shown, `the fingers 32 are of such a length that when the lays are lowered and the lay bar 12 is in its extreme foremost position the ends of the fingers 33 are disposed below the plane of the top of the bar 22. Hence if the sheet 21 over-runs the lays, the fingers 32 engage the leading end of the sheet 21 and are arrested by it. In these circumstances, the fingers 32 remain stationary on the sheet 21 during the final descending movement of the lays.

Each split block 27 has fixed to it a plate 36 of insulating material carrying a contact spring 37 which extends forwardly over the corresponding over-run finger 32 with its forward end in proximity to the finger whereoy the finger makes contact with the spring 37 if it is held stationary by a sheet of paper during the final descending movement of the lays. A terminal 38 is mounted on the plate 36 in electrical Contact with the spring 37, and a. second terminal 39 is mounted on the plate 36 in electrical contact withthe block 27. Hence when the finger 32 contacts the leaf 37 it completes an electrical circuit between the terminals 3S and 39.

The mechanism also includes a switch 40 fixed to one of the side plates 11 and having an operating arm 41 which projects rearwardly therefrom. A lever 42 is fixed to the lay bar 12 so as to extend rearwardly therefrom and is arranged so that in the extreme forward position of the lay bar 12 shown in FIGURE 4, the lever 42 engages the arm 41 and holds it in a position to close the contacts of the switch 40. The switch 40 is arranged so that when the arm 41 is not urged upwardly by the lever 42 the switch contacts are open. The switch means provided by the fingers leaves and terminals of each block 27 are connected in parallel with each other and in series with the switch 40 in an electrical control circuit which is arranged to stop the machine. The machine in question is commonly provided with a safety switch 101 (see FIG. 8) for operation by a jamb bar arranged to be raised if the stream of sheets moving towards the lays is excessively thick. This safety switch 101 operates to close an electrical circuit 102 which is used to stop the machine, and therefore the circuit of the switch 40 and the associated finger operated switches described above may be connected in parallel arrangement with this existing safety switch 101 to operate the same SOP- ping mechanism in the event of a sheet over-running the lays. v

When the lay bar 12 is in the rear position as illustrated in FIGURES 5 and 6 the lever 42 is withdrawn from the arm 41 of the switch 40, so that the contacts of the switch 40 are open, and in fact the contacts of the switch 40 are closed only in that part of the cycle of the machine in which the lay bar is in the vicinity of its forward angular position shown in FIGURES 3 and 4. If either of the over-run ngers 32 is raised when the contacts of the switch 40 are open, the circuit 102 is not closed. Hence if the fingers 32 aret engaged by the upwardly turned following end of a correctly fed sheet, the control circuit is not completed and the machine is not stopped. However if a sheet is fed forwardly incorrectly and over-runs the lays it is engaged by one or both of the over-run fingers 32 while the contacts of the switch 40 are closed and hence the circuit 102 is completed and the control mechanism is operated to stop the machine.

The safety means illustrated also includes means for actuating the under-feed trip mechanism if either of the over-run fingers 32 fails to complete its downward movement. The additional mechanism comprises a pawl 43 pivotally mounted on the spigot of each rocker 30 and extending rearwardly'therefroni.- Each'pawl 43'is arl' ranged to rest slidably on the upper surface of a stop plate 44 extending laterally from the corresponding depending arm 14. Each pawl 43 is provided on its lower surface, forwardly of its rear end, with a rearwardly facing shoulder 45 disposed in the path of movement of the forward edge of the corresponding stop plate 44. Each pawl 43 has a laterally projecting lug 46 carrying an adjustable stop screw 47 the end of which is disposed to engage the upper surface of the rearwardly projecting tail 31 of the rocker 30. Each of the screws 47 is normally adjusted so that when the lay 'oar is inthe forward position shown in FIGURE 3, and the paper is being fed correctly so that the over-run fingers 32 are also positioned as shown in FIGURE 3, the tail 31 of each rocker 30 holds the corresponding pawl 43 (through the agency of the screw 47) so that the shoulder 45 is clear of the stop plate 44. Thus the pawls do not prevent the depending arms 14 and the trip spindle 13 from completing their forward movements. However, if a sheet over-runs so that one or both of the fingers 32 are lheld in the position shown in FIGURE 7 when the lay bar 12 has reached its extreme forward position, one or Iboth of the pawls 43 are not lifted to the same extent, and one or both of the shoulders 45 are disposed so as to be engaged by the forward edge of the stop plates 44. Thus, the trip mechanism then operates in the usual manner to stop the feeder.

The invention therefore provides trip mechanism which operates automatically to stop the machine and prevent damage thereto in the event of the over-feeding of a sheet, and also to stop further feeding of paper in the same circumstances. The mechanism is simple and comparatively inexpensive and can be easily and quickly fitted to existing machines of the aforesaid kind making use of existing stop and trip mechanism incorporated therein.

Weclaim:

yl. ln a sheet feeding device for printing machines a safety mechanism having a lay shaft, means for oscillating said lay shaft in timed relation to the operation of the printing machine, means partaking in the oscillations of said lay shaft for detecting sheets incorrectly positioned by the said feeding device, and means actuated by the said detecting means for interrupting the feeding of the sheets, said means including a block on and turnable with the lay shaft, a pivot pin on said block rearwardly of said lay shaft, a feeler-finger extending forwardly and capable of limited turning movement on said pivot pin in relation to said lay shaft, said finger having a downwardly projecting end portion, resilient means normally urging said finger so as to protrude with its downwardly projecting end portion into contact with the edges of the advancing sheets, means operable by the said finger for stopping the oscillation of said lay shaft and, thereby, arresting the feeding of the sheets when the downward movement of the finger becomes interrupted by its end portion striking the leading part of an overfed sheet, an electric terminal mounted on the rlinger-supporting block insulated therefrom, a contact spring on said terminal extending into the vicinity of said finger to be actuated thereby when the downward movement of said linger is interrupted, another terminal in electric connection with said block and said contact spring for closing an electric circuit, and means in said electric circuit for interrupting the feeding of the sheets upon closing of the circuit.

2. In a sheet feeding device for printing machines a safety mechanism having a lay shaft, means for oscillating said lay shaft in timed relation to the operation of the printing machine, means partaking in the oscillations of said lay yshaft for detecting sheets incorrectly positioned by the said feeding device, and means actuated by the said detecting means for interrupting the feeding of the sheets, said means including a block on and turnable with the lay shaft, a pivot pin on said block rearwardly of said lay shaft, a feeler-iinger extending forwardly and capable of limited turning movement on said pivot pin in relation to said lay shaft, said nger having a downwardly projecting end portion, resilient means normally urging said iinger so as to protrude with its downwardly projecting end portion into contact with the edges of the advancing sheets, means -operable by the said finger yfor stopping the oscillation of said lay shaft and, thereby, arresting the feeding of the sheets when the downward movement of the finger becomes interrupted by its end portion striking the leading part of an overfed sheet, an electric switch on the lay shaft, a switch member operable by the detector nger when turned .in opposition to its resilient means, another switch on a stationary part of the printing machine, an arm on said lay shaft to operate said switch member so as to close a circuit between the first-named and the second-named switches, and electrically operated means in the said circuit for stopping the oscillatory movement of the lay bar and, thereby, interrupting the feeding of the sheets when the first-named switch is closed by the movement of said detector finger in opposition to said resilient means.

References Cited in the le of this patent UNITED STATES PATENTS 2,165,535 Brownsey July 11, 1939 2,395,740 Hileman et al Feb. 26, 1946 2,634,972 Kelly Apr. 14, 1953 2,709,960 Alix et al June 7, 1955 2,721,737 Hammer et al Oct. 25, 1955 

